# *****************************************************************************
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# Module authors:
#   Markus Zolliker <markus.zolliker@psi.ch>
#
# *****************************************************************************

"""drivers for CCU4, the cryostat control unit at SINQ"""
import time
import math
from frappy.lib.enum import Enum
from frappy.lib import clamp
# the most common Frappy classes can be imported from frappy.core
from frappy.core import HasIO, Parameter, Command, Readable, Writable, Drivable, \
    Property, StringIO, BUSY, IDLE, WARN, ERROR, DISABLED, Attached, nopoll
from frappy.datatypes import BoolType, EnumType, FloatRange, StructOf, \
    StatusType, IntRange, StringType, TupleOf
from frappy.errors import CommunicationFailedError
from frappy.states import HasStates, status_code, Retry


M = Enum(idle=0, opening=1, closing=2, opened=3, closed=4, no_motor=5)
A = Enum(disabled=0, manual=1, auto=2)


class IO(StringIO):
    """communication with CCU4"""
    # for completeness: (not needed, as it is the default)
    end_of_line = '\n'
    # on connect, we send 'cid' and expect a reply starting with 'CCU4'
    identification = [('cid', r'cid=CCU4.*')]


class Base(HasIO):
    ioClass = IO

    def command(self, **kwds):
        """send a command and get the response

        :param kwds: <parameter>=<value> for changing a parameter <parameter>=<type> for querying a parameter
        :returns: the (new) values of the parameters
        """
        types = {}
        cmds = []
        for key, value in kwds.items():
            if isinstance(value, type):
                types[key] = value
                cmds.append(key)
            elif isinstance(value, str):
                types[key] = str
                cmds.append(f'{key}={value}')
            else:
                types[key] = float
                cmds.append(f'{key}={value:g}')
        reply = self.io.communicate(' '.join(cmds)).split()
        if len(reply) != len(types):
            raise CommunicationFailedError('number of reply items does not match')
        result = []
        for (given, typ), res in zip(types.items(), reply):
            name, txtvalue = res.split('=')
            if given != name:
                raise CommunicationFailedError('result keys do not match given keys')
            result.append(typ(txtvalue))
        if len(kwds) == 1:
            return result[0]
        return result


class HeLevel(Base, Readable):
    """He Level channel of CCU4"""

    value = Parameter(unit='%')
    empty_length = Parameter('warm length when empty', FloatRange(0, 2000, unit='mm'),
                             readonly=False)
    full_length = Parameter('warm length when full', FloatRange(0, 2000, unit='mm'),
                            readonly=False)
    sample_rate = Parameter('sample rate', EnumType(slow=0, fast=1), readonly=False)

    status = Parameter(datatype=StatusType(Readable, 'DISABLED'))

    # conversion of the code from the CCU4 parameter 'hsf'
    STATUS_MAP = {
        0: (IDLE, 'sensor ok'),
        1: (ERROR, 'sensor warm'),
        2: (ERROR, 'no sensor'),
        3: (ERROR, 'timeout'),
        4: (ERROR, 'not yet read'),
        5: (DISABLED, 'disabled'),
    }

    def read_value(self):
        return self.command(h=float)

    def read_status(self):
        return self.STATUS_MAP[int(self.command(hsf=int))]

    def read_sample_rate(self):
        value, self.empty_length, self.full_length = self.command(hf=int, hem=float, hfu=float)
        return value

    def write_sample_rate(self, value):
        return self.command(hf=value)

    def write_empty_length(self, value):
        return self.command(hem=value)

    def write_full_length(self, value):
        return self.command(hfu=value)


class Valve(Base, Writable):
    value = Parameter('relay state', BoolType())
    target = Parameter('relay target', BoolType())
    ioClass = IO
    STATE_MAP = {0: (0, (IDLE, 'off')),
                 1: (1, (IDLE, 'on')),
                 2: (0, (ERROR, 'no valve')),
                 3: (0, (WARN, 'timeout')),  # timeout in filling process (takes too long to fill)
                 4: (0, (WARN, 'timeout1')),  # timeout in filling process (takes too long to start)
                 5: (1, (IDLE, 'boost')),
                 }
    _open_command = None
    _close_command = None
    _query_state = None

    def write_target(self, target):
        if target:
            self.command(**self._open_command)
        else:
            self.command(**self._close_command)

    def read_status(self):
        state = int(self.command(**self._query_state))
        self.value, status = self.STATE_MAP[state]
        return status


class HeFillValve(Valve):
    _open_command = {'hcd': 1, 'hf': 1}
    _close_command = {'hcd': 0,  'hf': 0}
    _query_state = {'hv': int}


class N2FillValve(Valve):
    _open_command = {'nc': 1}
    _close_command = {'nc': 0}
    _query_state = {'nv': int}


class AuxValve(Valve):
    channel = Property('valve number', IntRange(1, 12))

    def initModule(self):
        self._open_command = {f'vc{self.channel}': 1}
        self._close_command = {f'vc{self.channel}': 0}
        self._query_state = {f'v{self.channel}': int}


class N2TempSensor(Readable):
    value = Parameter('LN2 T sensor', FloatRange(unit='K'), default=0)


class N2Level(Base, Readable):
    valve = Attached(Writable, mandatory=False)
    lower = Attached(Readable, mandatory=False)
    upper = Attached(Readable, mandatory=False)

    value = Parameter('vessel state', EnumType(empty=0, ok=1, full=2))
    status = Parameter(datatype=StatusType(Readable, 'DISABLED', 'BUSY'))
    mode = Parameter('auto mode', EnumType(A), readonly=False, default=A.manual)

    threshold = Parameter('threshold triggering start/stop filling',
                          FloatRange(unit='K'), readonly=False)
    cool_delay = Parameter('max. minutes needed to cool the lower sensor',
                           FloatRange(unit='s'), readonly=False)
    fill_timeout = Parameter('max. minutes needed to fill',
                             FloatRange(unit='s'), readonly=False)
    names = Property('''names of attached modules

                     configure members as empty strings to disable the creation
                     ''',
                     StructOf(valve=StringType(), lower=StringType(), upper=StringType()),
                     default={'valve': '$_valve', 'lower': '$_lower', 'upper': '$_upper'})

    # conversion of the code from the CCU4 parameter 'ns'
    STATUS_MAP = {
        0: (IDLE, 'sensor ok'),
        1: (ERROR, 'no sensor'),
        2: (ERROR, 'short circuit'),
        3: (ERROR, 'upside down'),
        4: (ERROR, 'sensor warm'),
        5: (WARN, 'empty'),
    }

    def initialReads(self):
        self.command(nav=1)  # tell CCU4 to activate LN2 sensor readings
        super().initialReads()

    def read_status(self):
        auto, nstate = self.command(na=int, ns=int)
        if not self.valve or not auto:
            if self.mode == A.auto:
                # no valve assigned
                self.mode = A.manual
        if self.mode == A.disabled:
            return DISABLED, ''
        status = self.STATUS_MAP[nstate]
        if status[0] // 100 != IDLE // 100:
            return status
        if self.mode == A.manual:
            return IDLE, ''
        vstatus = self.valve.status
        if vstatus[0] // 100 == WARN // 100:
            return ERROR, vstatus[1]
        if vstatus[0] // 100 != IDLE // 100:
            return vstatus
        if self.valve.value:
            return BUSY, 'filling'
        return IDLE, 'watching'

    def read_value(self):
        # read sensors
        lower, upper = self.command(nl=float, nu=float)
        if self.lower:
            self.lower.value = lower
        if self.upper:
            self.upper.value = upper
        if upper < self.threshold:
            return 'full'
        if lower < self.threshold:
            return 'ok'
        return 'empty'

    def write_mode(self, mode):
        if mode == A.auto:
            if self.isBusy():
                return mode
            # set to watching
            self.command(nc=3)
        else:
            # set to off
            self.command(nc=2)
        return mode

    def read_threshold(self):
        value, self.cool_delay, self.fill_timeout = self.command(nth=float, ntc=float, ntm=float)
        return value

    def write_threshold(self, value):
        return self.command(nth=value)

    def write_cool_delay(self, value):
        return self.command(ntc=value)

    def write_fill_timeout(self, value):
        return self.command(ntm=value)

    @Command()
    def fill(self):
        """start filling"""
        self.mode = A.auto
        self.command(nc=1)

    @Command()
    def stop(self):
        """stop filling"""
        if self.mode == A.auto:
            # set to watching
            self.command(nc=3)
        else:
            # set to off
            self.command(nc=0)


class HasFilter:
    __value1 = None
    __value = None
    __last = None

    def filter(self, filter_time, value):
        now = time.time()
        if self.__value is None:
            self.__last = now
            self.__value1 = value
            self.__value = value
        weight = (now - self.__last) / filter_time
        self.__value1 += weight * (value - self.__value)
        self.__value += weight * (self.__value1 - self.__value)
        self.__last = now
        return self.__value


class Pressure(HasFilter, Base, Readable):
    value = Parameter(unit='mbar')
    mbar_offset = Parameter('offset in mbar', FloatRange(unit='mbar'), default=0.8, readonly=False)
    filter_time = Parameter('filter time', FloatRange(unit='sec'), readonly=False, default=3)
    pollinterval = Parameter(default=0.25)

    def read_value(self):
        return self.filter(self.filter_time, self.command(f=float)) - self.mbar_offset


class NeedleValveFlow(HasStates, Base, Drivable):
    flow_sensor = Attached(Readable, mandatory=False)
    pressure = Attached(Pressure, mandatory=False)
    use_pressure = Parameter('flag (use pressure instead of flow meter)', BoolType(),
                             readonly=False, default=False)
    lnm_per_mbar = Parameter('scale factor', FloatRange(unit='lnm/mbar'), readonly=False, default=0.6)

    value = Parameter(unit='ln/min')
    target = Parameter(unit='ln/min')

    motor_state = Parameter('motor_state', EnumType(M), default=0)
    tolerance = Parameter('tolerance', FloatRange(0), value=0.25, readonly=False)
    tolerance2 = Parameter('tolerance limit above 2 lnm', FloatRange(0), value=0.5, readonly=False)
    prop = Parameter('proportional term', FloatRange(unit='s/lnm'), readonly=False, default=0.001)
    deriv = Parameter('min progress time constant', FloatRange(unit='s'),
                      default=30, readonly=False)
    settle = Parameter('time within tolerance before getting quiet', FloatRange(unit='s'),
                       default=30, readonly=False)
    step_factor = Parameter('factor (no progress time) / (min step size)', FloatRange(), default=300, readonly=False)
    control_active = Parameter('control active flag', BoolType(), readonly=False, default=1)
    min_open_step = Parameter('minimal open step', FloatRange(unit='s'), readonly=False, default=0.06)
    min_close_step = Parameter('minimal close step', FloatRange(unit='s'), readonly=False, default=0.05)
    raw_open_step = Parameter('step after direction change', FloatRange(unit='s'), readonly=False, default=0.12)
    raw_close_step = Parameter('step after direction change', FloatRange(unit='s'), readonly=False, default=0.04)
    pollinterval = Parameter(default=5)
    _ref_time = 0
    _ref_dif = 0
    _dir = 0
    _rawdir = 0
    _step = 0

    def initModule(self):
        if self.pressure:
            self.pressure.addCallback('value', self.update_from_pressure)
        if self.flow_sensor:
            self.flow_sensor.addCallback('value', self.update_from_flow)
        super().initModule()

    def update_from_flow(self, value):
        if not self.use_pressure:
            self.value = value
            # self.cycle_machine()

    def update_from_pressure(self, value):
        if self.use_pressure:
            self.value = value * self.lnm_per_mbar
            # self.cycle_machine()

    # def doPoll(self):
    #     """only the updates should trigger the machine"""

    def read_value(self):
        p = self.pressure.read_value() * self.lnm_per_mbar
        f = self.flow_sensor.read_value()
        # self.log.info('p %g f %g +- %.2g', p, f, self.flow_sensor.stddev)
        self.read_motor_state()
        return p if self.use_pressure else f

    def write_tolerance(self, tolerance):
        if hasattr(self.pressure, 'tolerance'):
            self.pressure.tolerance = tolerance / self.lnm_per_mbar
        if hasattr(self.flow_sensor, 'tolerance'):
            self.flow_sensor.tolerance = tolerance

    def read_use_pressure(self):
        if self.pressure:
            if self.flow_sensor:
                return self.use_pressure
            return True
        return False

    def write_target(self, value):
        self.start_machine(self.change_target, fast_poll=1)

    @status_code(BUSY)
    def change_target(self, state):
        state.in_tol_time = 0
        state.last_minstep = {}
        state.last_progress = state.now
        state.ref_time = 0
        state.ref_dif = 0
        state.prev_dif = 0  # used?
        state.last_close_time = 0
        state.last_pulse_time = 0
        state.raw_fact = 1
        state.raw_step = 0
        if abs(self.target - self.value) < self._tolerance():
            return self.at_target
        return self.raw_control

    def start_direction(self, state):
        if self.target > self.value:
            self._dir = 1
            state.minstep = self.min_open_step
        else:
            self._dir = -1
            state.minstep = self.min_close_step
        state.prev = []

    def perform_pulse(self, state):
        tol = self._tolerance()
        dif = self.target - self.value
        difdir = dif * self._dir
        state.last_pulse_time = state.now
        if difdir > tol:
            step = state.minstep + (difdir - tol) * self.prop
        elif difdir > 0:
            step = state.minstep * difdir / tol
        else:
            return
        self.log.info('MP %g dif=%g tol=%g', step * self._dir, dif, tol)
        self.command(mp=clamp(-1, step * self._dir, 1))

    @status_code(BUSY)
    def raw_control(self, state):
        tol = self._tolerance()
        if state.init:
            self.start_direction(state)
            state.raw_step = self.raw_open_step if self._dir > 0 else -self.raw_close_step
            state.raw_fact = 1
            # if self.read_motor_state() == M.closed:
            #     # TODO: also check for flow near lower limit ? but only once after change_target
            #     self.log.info('start with fast opening')
            #     state.raw_step = 1
            #     self._dir = 1
            difdir = (self.target - self.value) * self._dir
            state.prev.append(difdir)
            state.diflim = max(0, difdir - tol * 1)
            state.success = 0
            self.command(mp=state.raw_step)
            self.log.info('first rawstep %g', state.raw_step)
            state.last_pulse_time = state.now
            state.raw_pulse_cnt = 0
            state.cycle_cnt = 0
            return Retry
        difdir = (self.target - self.value) * self._dir
        state.cycle_cnt += 1
        state.prev.append(difdir)
        del state.prev[:-5]
        if state.prev[-1] > max(state.prev[:-1]):
            # TODO: use the amount of overshoot to reduce the raw_step
            state.cycle_cnt = 0
            self.log.info('difference is increasing %s', ' '.join(f'{v:g}' for v in state.prev))
            return Retry
        if state.cycle_cnt >= 5:
            state.cycle_cnt = 0
            state.diflim = max(tol, min(state.prev) - tol * 0.5)
            state.raw_pulse_cnt += 1
            self.command(mp=state.raw_step * state.raw_fact)
            self.log.info('rawstep %g', state.raw_step)
            if state.raw_pulse_cnt % 5 == 0 and state.raw_pulse_cnt > 5:
                state.raw_fact *= 1.25
            return Retry
        if difdir >= state.diflim:
            state.success = max(0, state.success - 1)
            return Retry
        state.success += 1
        if state.success <= 3:
            return Retry
        if state.raw_pulse_cnt < 3:
            state.raw_fact = 1 - (3 - state.raw_pulse_cnt) ** 2 * 0.05
        if state.raw_fact != 1:
            if self._dir > 0:
                self.raw_open_step *= state.raw_fact
                self.log.info('raw_open_step %g f=%g', self.raw_open_step, state.raw_fact)
                self.min_open_pulse = min(self.min_open_pulse, self.raw_open_step)
            else:
                self.raw_close_step *= state.raw_fact
                self.log.info('raw_close_step %g f=%g', self.raw_close_step, state.raw_fact)
                self.min_close_pulse = min(self.min_close_pulse, self.raw_close_step)
        return self.controlling

    # @status_code(BUSY)
    # def raw_control(self, state):
    #     tol = self._tolerance()
    #     if state.init:
    #         self.start_direction(state)
    #         if self._dir != self._rawdir:
    #             self._rawdir = self._dir
    #             state.first_step = self.first_open_step if self._dir > 0 else -self.first_close_step
    #         else:
    #             state.first_step = 0
    #         state.first_fact = 1
    #         # if self.read_motor_state() == M.closed:
    #         #     # TODO: also check for flow near lower limit ? but only once after change_target
    #         #     self.log.info('start with fast opening')
    #         #     state.first_step = 1
    #         #     self._dir = 1
    #         difdir = (self.target - self.value) * self._dir
    #         state.prev = [difdir]
    #         state.diflim = max(0, difdir - tol * 0.5)
    #         state.success = 0
    #         if state.first_step:
    #             self.command(mp=state.first_step)
    #         else:
    #             self.perform_pulse(state)
    #         self.log.info('firststep %g', state.first_step)
    #         state.last_pulse_time = state.now
    #         state.raw_pulse_cnt = 0
    #         return Retry
    #     difdir = (self.target - self.value) * self._dir
    #     if state.delta(5):
    #         state.diflim = max(0, min(state.prev) - tol * 0.1)
    #         state.prev = [difdir]
    #         state.raw_pulse_cnt += 1
    #         if state.first_step and state.raw_pulse_cnt % 10 == 0:
    #             self.command(mp=state.first_step * state.first_fact)
    #             self.log.info('repeat firststep %g', state.first_step * state.first_fact)
    #             state.first_fact *= 1.25
    #         else:
    #             self.perform_pulse(state)
    #         return Retry
    #     state.prev.append(difdir)
    #     if difdir >= state.diflim:
    #         state.success = max(0, state.success - 1)
    #         return Retry
    #     state.success += 1
    #     if state.success <= 5:
    #         return Retry
    #     if state.first_step:
    #         if state.raw_pulse_cnt < 3:
    #             state.first_fact = 1 - (3 - state.raw_pulse_cnt) ** 2 * 0.04
    #         if state.first_fact != 1:
    #             if self._dir > 0:
    #                 self.first_open_step *= state.first_fact
    #                 self.log.info('first_open_step %g f=%g', self.first_open_step, state.first_fact)
    #             else:
    #                 self.first_close_step *= state.first_fact
    #                 self.log.info('first_close_step %g f=%g', self.first_close_step, state.first_fact)
    #     return self.controlling

    @status_code(BUSY)
    def controlling(self, state):
        dif = self.target - self.value
        if state.init:
            self.start_direction(state)
            state.ref_dif = abs(dif)
            state.ref_time = state.now
            state.in_tol_time = 0
        difdir = dif * self._dir  # negative when overshoot happend
        # difdif = dif - state.prev_dif
        # state.prev_dif = dif
        expected_dif = state.ref_dif * math.exp((state.ref_time - state.now) / self.deriv)

        tol = self._tolerance()
        if difdir < tol:
            # prev_minstep = state.last_minstep.pop(self._dir, None)
            # attr = 'min_open_step' if self._dir > 0 else 'min_close_step'
            # if prev_minstep is not None:
            #     # increase minstep
            #     minstep = getattr(self, attr)
            #     setattr(self, attr, minstep * 1.1)
            #     self.log.info('increase %s to %g', attr, minstep)
            if difdir > -tol:  # within tolerance
                delta = state.delta()
                state.in_tol_time += delta
                if state.in_tol_time > self.settle:
                    # state.last_minstep.pop(self._dir, None)
                    self.log.info('at target %g %g', dif, tol)
                    return self.at_target
                if difdir < 0:
                    return Retry
                # self.log.info('minstep=0 dif=%g', dif)
            else:  # overshoot
                self.log.info('overshoot %g', dif)
                return self.raw_control
                # # overshoot
                # prev_minstep = state.last_minstep.pop(self._dir, None)
                # if prev_minstep is None:
                #     minstep = getattr(self, attr) * 0.9
                #     self.log.info('decrease %s to %g', attr, minstep)
                #     setattr(self, attr, minstep)
                # self.start_step(state, self.target)
        # still approaching
        if difdir <= expected_dif:
            if difdir < expected_dif / 1.25 - tol:
                state.ref_time = state.now
                state.ref_dif = (difdir + tol) * 1.25
                # self.log.info('new ref %g', state.ref_dif)
            state.last_progress = state.now
            return Retry  # progressing: no pulse needed
        if state.now < state.last_pulse_time + 2.5:
            return Retry
        # TODO: check motor state for closed / opened ?
        self.perform_pulse(state)
        return Retry

    def _tolerance(self):
        return min(self.tolerance * min(1, self.value / 2), self.tolerance2)

    @status_code(IDLE)
    def at_target(self, state):
        dif = self.target - self.value
        if abs(dif) > self._tolerance():
            state.in_tol_time = 0
            self.log.info('unstable %g', dif)
            return self.unstable
        return Retry

    @status_code(IDLE, 'unstable')
    def unstable(self, state):
        difdir = (self.target - self.value) * self._dir
        if difdir < 0 or self._dir == 0:
            return self.raw_control
        return self.controlling(state)

    def read_motor_state(self):
        return self.command(fm=int)

    @Command
    def close(self):
        """close valve fully"""
        self.command(mp=-60)
        self.motor_state = self.command(fm=int)
        self.start_machine(self.closing)

    @status_code(BUSY)
    def closing(self, state):
        if state.init:
            state.start_time = state.now
        self.read_motor_state()
        if self.motor_state == M.closing:
            return Retry
        if self.motor_state == M.closed:
            return self.final_status(IDLE, 'closed')
        if state.now < state.start_time + 1:
            return Retry
        return self.final_status(IDLE, 'fixed')

    @Command
    def open(self):
        """open valve fully"""
        self.command(mp=60)
        self.read_motor_state()
        self.start_machine(self.opening)

    @status_code(BUSY)
    def opening(self, state):
        if state.init:
            state.start_time = state.now
        self.read_motor_state()
        if self.motor_state == M.opening:
            return Retry
        if self.motor_state == M.opened:
            return self.final_status(IDLE, 'opened')
        if state.now < state.start_time + 1:
            return Retry
        return self.final_status(IDLE, 'fixed')

    @Command(FloatRange())
    def pulse(self, value):
        """perform a motor pulse"""
        self.log.info('pulse %g', value)
        self.command(mp=value)
        if value > 0:
            self.motor_state = M.opening
            return self.opening
        self.motor_state = M.closing
        return self.closing